Warm weather has people heading to the lake, but before you take a dip local health officials hope you’ll heed their warning: a nasty parasite may be coming to a beach near you.

On Thursday, the Municipality of Anchorage confirmed the season's first reported case of swimmer's itch at Jewel Lake. Staff quickly put up signs letting people know that schistosomes, the parasitic flatworms which commonly cause the skin rash, are in the water.

The muni’s aquatic superintendent, Scott O’Brien, says such cases are reported every year at both Jewel Lake and Goose Lake. While the parasite isn’t dangerous, a bad case of swimmer’s itch can certainly ruin a summer day.

“I would compare it to kind of like a bunch of mosquito bites," O’Brien said. “It’s irritating, itchy, not life-threatening -- just annoying.”

Anchorage lakes are prone to swimmer’s itch in the middle to later summer months, according to the muni’s website.

Swimmer's itch parasites are commonly found in healthy freshwater. They spend their life cycles moving from small snails to ducks or geese. When the weather gets warm and the water heats, they become more active in shallow waters.

When they're active, the parasites often mistake human legs for the skin of a duck or goose.

“Within minutes to days after swimming in contaminated water, you may experience tingling, burning, or itching of the skin. Small reddish pimples appear within 12 hours. Pimples may develop into small blisters. Itching may last up to a week or more, but will gradually go away,” according to the muni’s website.

Anchorage Assembly member Felix Rivera was enjoying a swim Friday morning in Jewel Lake when a KTVA reporter informed him of the swimmer's itch case. He said unfortunately he didn’t see the signs.

“We just came swimming to have some fun and didn't realize that there was some swimmer's itch going on,” Rivera said. “When I hear that I think, 'Gosh, do I really want to be in this lake again?' It definitely concerns me.”

O’Brien said he’s never had swimmer’s itch but his kids have. He says one of the first things you can do if you start itching is get out of the water and towel off immediately.

“It is just an allergic reaction to a parasite that is in the water, and if you air dry it gives it more of a chance to get in there," O'Brien said. "So if you towel off really hard as soon as you get out of the water it should help prevent it.”

Beyond reducing its effects, O'Brien said, people shouldn't avoid going in the water just to avoid swimmer's itch.

It is up to people to decide for themselves if taking a dip is worth the risk.

Copyright 2018 KTVA. All rights reserved.